1. F. Buckley and F. Harary, Distance in Graphs, Addison-Wesley, Redwood City, CA, 1990.
2. F. Buckley and F. Harary, L.v. Quintas, Extremal results on the geodetic number of a graph, Scientia A2(1998) 17–26.
3. On the geodetic number of a graph
4. G. Chartrand, G.L.Johns, and P.Zhang, On the Detour Number and Geodetic Number of a Graph, Ars Combinatoria, 72(2004), 3–15.
5. G. Chartrand, E.M. Palmer, P. Zhang, The geodetic number of a graph, A survey, Congr. Numer. 156(2002)37–58.